Generally, in a door lock, a latch bolt is inserted into a latch bolt insertion groove formed at a door frame, and a locking state is maintained. At this time, an insertion depth of the latch bolt inserted into the latch bolt insertion groove is shallow in about 15 mm. In the case of the door lock having the insertion depth of the latch bolt, the latch bolt may be forcibly separated from the latch bolt insertion groove using a tool such as a screwdriver, and a door may be easily opened. Therefore, a double locking device is required.
If the insertion depth of the latch bolt inserted into the latch bolt insertion groove is deep, for example, in about 20 mm or more, this problem may be solved. However, in a conventional cylindrical or tubular door lock in which a door handle is rotated to open a door, a rotational angle of the door handle is increased, and thus it is inconvenient to open the door.
Meanwhile, in the conventional cylindrical or tubular door lock, while the door handle is rotated, the door should be pushed or pulled to open and close the door. Therefore, in the case of persons with physical handicap and reduced mobility, such as children, patients, and disabled persons, as well as normal persons, it is not easy to open and close the door.
Therefore, a push-pull door lock in which the door handle is pushed or pulled to open and close the door had been proposed to easily open and close the door. However, such a conventional door lock has some problems that a structure thereof is complicated, manufacturing cost is increased due to so many components, and a separate reconstruction work with respect to the door is required when the existing cylindrical or tubular door lock is replaced with the push-pull door lock.
Further, in the conventional door lock, since the insertion depth of the latch bolt inserted into the latch bolt insertion groove may not be increased beyond a predetermined depth, it has low safety, and thus the double locking device may be required.
Furthermore, since the conventional push-pull door locks have different structures from each other, an exclusive door handle is required. Therefore, even if there is a door handle having a design desired by a user, it may not be used if the selected door handle is not suitable for the door lock to be installed.